A shutter assembly typically comprises a frame and a plurality of vertically spaced horizontal louvres. The louvres are rotatably adjustable to tilt to and fro to exclude light or to admit light.
Generally, such shutter assemblies have a rectangular frame comprised of vertically and horizontally spaced side portions. The frame is mounted around a doorway window or opening, and is securely held in place by fasteners, passing through the shutter frame. The shutter is mounted in the frame.
In many cases it is desirable to provide such a border frame with an aesthetic shape or design. The actual shutter can be placed within the border frame, and the combination provides a pleasing appearance. Methods are known to conceal the fasteners, including counter-sinking, insertion of putty or synthetic wood over the head of a fastener, and final finishing by sanding, paint or other material. All these methods have significant disadvantages because they require expensive tools, carpentry expertise and time to apply them. In the past shutters were usually made of wood for simplicity and for aesthetics.
Materials such as plastics, especially extruded plastics, have many advantages over wood. However fabrication techniques in plastics have not kept pace with the consumer demand to decorate homes and offices with shutters.
Consumers require plastic shutters having an appearance similar to wooden shutters. Fabricating shutters and the border frames from plastic components, which simulate wood can be a challenge.
Wooden shutters and wooden frames are shaped with a solid comfortable appearance, and define substantial thickness and attractive contours and shapes.
Wooden shutter frames may be milled out of a solid piece of wood. Thus the profile of the frame may be given a variety of shapes, for decorative effect.
Achieving this look with plastic components is not as simple as it may appear.
The plastic border frame should preferably have contouring comparable to the contours of a wooden window or door frame.
Plastic shutters are usually made with frames which are of plain rectangular cross section. In order to provide a border frame with the same decorative effect as a milled wooden frame, it is desirable to fabricate a separate border frame, into which the actual shutter can be seated and secured.
Making such border framing out of extruded plastic, requires great care. Plastics generally are unsuitable for creating solid shapes. Some plastics are exceptions to this but for so called thermoplastics it is necessary that they be formed with sections which are thin and cool easily without distortion. Economy of material is another reason for this.
When fabricating sections such as border frames for shutters, out of plastic, it is desirable to form such sections by extrusion. Lengths of sections can be made in this way. The sections can then be cut to length to fabricate the four sides of the frame of a particular shutter. In addition the border frame must be fastened to the building fabric, around the window by fasteners.
For aesthetic reasons, it is desirable to conceal heads of the fasteners after the installation.
Such extrusions are designed with a series of hollow channels or tubes, defined by a number of walls extending through the section. The actual thickness of any wall is relatively thin. Extruding such sections with a large number of hollow tubes is itself a challenge. The dies must be designed to allow the plastic to be extruded while hot, and flowable. After extrusion, the chilling of the extruded section must be achieved in such a way as to maintain, as far as possible, the integrity of the entire design.
To achieve all this the section of the extrusion must be designed to facilitate this, while at the same time producing a pleasing aesthetic appearance, on the exterior.
Added to all these considerations there is a need for a shutter assembly designed for manufacture from thermoplastic material having a border frame that includes a recess or fastener channel to receive fasteners. Preferably a removable extruded plastic plug in the form of an inverted three sided channel, is provided to cover the fasteners without the requirement for tools and carpentry expertise.
Such border frame sections must also be capable of being securely joined at the four corners, so as to form a rigid four sided border frame. The extrusion must therefor be designed in such a way that it can accommodate corner junctions and reinforcements.
This need may be addressed by forming the border frame section for the border frame with a recessed fastener channel for fasteners and a cover plug channel that is inverted and fitted into the fastener channel to cover the heads of the fasteners.
In U.S. Letters Pat. No. 6,474,038, Window Shutter Frame Assembly and Method of Installation, there is shown a frame with a basic form of fastener concealment system, but it is designed for wooden shutters with solid components.
This type of system was restricted to shutters having wooden frames. The wooden frames have a channel for the fasteners, and a solid wooden bead is shaped for insertion into the channel.
This wooden system lacks flexibility and is not adaptable to use with shutter frames formed of extruded plastic material. It is also incapable of receiving corner junctions for extra strength. This may reduce its working life.
In addition to these considerations, there is also a problem with the actual depth of a particular shutter. Shutters having wider louvres will have a rectangular frame which is relatively deep. Shutters having louvres which are of lesser width will have a frame which is less deep.
Preferably the border frame may be adaptable to provide greater or lesser depth. It is therefor desirable to provide extension members, similar to “shims” which can be added to the border frame to give it increased depth.